1. Field of the Invention
This invention relates to a cistern flushing apparatus.
2. Description of Background Art
Cistern flushing systems are known in which a valve stem carries a closure member which is normally seated upon an outlet from the cistern. The valve stem is raised by an operating system to unseat the closure member from the outlet to permit flushing liquid to leave the cistern through the outlet, and the stem is held in its raised position by the action of a float arm. When the liquid level in the cistern drops to a certain level the float arm drops and ceases to act upon the stem with the result that the stem drops under gravity and reseats the closure member to end the flush.
A further known development to a system of the kind first specified provides the operator with a choice between different flush volumes. In this case there are two float arms at different levels. The operating system permits the stem selectively to be raised to two different heights. When the stem is raised to the lower of the two heights, it is only acted upon and held up by the upper of the float arms. When a partial flush only has taken place, the stem is released by the float arm with resultant dropping of the stem and reseating of the closure member on the outlet. On the other hand, when the stem is raised to the higher of the two heights, it is acted upon by the lower float arm which only releases it to drop down and reseat the closure member when a full flush has taken place.
A typical example of a system of the kind second specified is described in South African patent No. 75/0671. All the known operating systems make use of rotatable operating levers and appropriate linkages to achieve raising of the valve stem and unseating of the closure member to commence the flush. The present inventor has encountered difficulties with such systems, primarily caused by sticking of the operating lever(s).
It is an object of the present invention to provide a cistern flushing apparatus which has a different kind of operating system.